This invention relates generally to the field of internal combustion engines and more specifically to an internal combustion engine machine incorporating significant improvements in power, efficiency and emissions control.
This invention was conceived in response to the need for greater simplicity, efficiency and power in internal combustion piston engine designs.
Although two-stroke cycle engine technology has many advantages, it has deficiencies have caused widespread legislative restriction on its use and, in the US, an outright EPA ban on it by the year 2006.
Additionally, in nations where sophistication of publicly available technology is low, the prevalent two-cycle technology is producing high levels of air pollution and creating excessive fuel and lubricating oil expense due to the fact that the lubricating oil is burned along with the fuel in inefficient combustion. However, it is the only technology that the users can afford to acquire and maintain. This invention was conceived to defeat these problems.
Prior internal combustion piston engine technology has been divided into two primary groups, two-stroke cycle engines and four-stroke cycle engines. Prior two-stroke cycle engine technology has a number of advantages over four-stroke cycle technology. These advantages are a higher power to weight ratio and greater design simplicity that results in low production and maintenance costs. Four-stroke technology, on the other hand retained advantages over two-stroke technology in efficiency, dependability, and clean operation. No prior technology produced the advantages of both types in one engine.
Two Stroke Engine Technology Prior Art in General
Prior two-stroke cycle engines suffer a number of deficiencies. They are inefficient, up to or beyond ten times less efficient than comparable four-stroke cycle engines. They also inconveniently require that oil be measured and mixed with their fuel. As a result, prior two-stroke cycle engines operate much less cleanly than comparable four-stroke cycle engines, produce several times the volume of toxic emissions over that of comparable four-stroke cycle engines, experience a high incidence of plug fouling, are notoriously undependable, and use excessive fuel and lubricant.
Previous attempts at improved two-stroke technology have included linier engine configurations with pistons in each piston pair located diametrically opposite one another, as does this invention. One such popular configuration is popularly known as the “Bourke” engine. However, such previous linier designs have had a comparably narrow range of RPM speeds within which they could perform. These speeds are unsatisfactory for many applications and also complicate engine performance and design parameters for the various internal components.
Prevalent conventional engine technology causes wear on the many moving machine parts, largely due to components of articulated motion. This wear is concentrated, in particular, on the pistons, piston rings, cylinders, wrist pins, connecting rod bearings; main bearings and other related principal parts.
In present conventional engine technology, high operating temperatures bring increased complexity and expense in engine design and choice of materials.
Present conventional technology is not adaptable to attain significant energy savings by being run on fewer than all cylinders, when full power is not required, letting the unused cylinders and pistons disconnect from the drive train and come to complete rest until again needed.
Cylinder Head Exhaust Valve Prior Art
A number of cam or hydraulically controlled cylinder head exhaust valves are taught in prior two-stroke technology, but none were found teaching cylinder head exhaust valves applied to spark ignited two-stroke technology. However, spark ignition is the more compatible, and therefore overwhelmingly more dominant, configuration for lightweight engines. Therefore, this new use of a cylinder head exhaust valve in application to spark ignited two-stroke technology with the resultant increase in efficiency and reduction in toxic emissions is a much-needed improvement.
U.S. Pat. No. 2,097,883 to Johansson teaches an exhaust valve for two-stroke cycle diesel engines (i.e., not spark ignited). The valve in that patent is specifically designed to control combustion chamber pressure in compression ignition engines.
Oil Hoarding Rings Prior Art
No use of rings on a piston for the purpose of sealing the lubricated space and retaining oil between them has been found in prior technology. In fact, U.S. Pat. No. 4,364,307 teaches against such usage, particularly noting that it would be inappropriate to place sealing rings both above and below a lubrication groove. That, however, is precisely one design characteristic of this invention. Dynamic Pressure Pump, Double-Acting Piston Rod and Multi-Function Pistons to Carry, Distribute, and Recover Lubrication Oil A number of patents teach the transport of lubrication oil via a piston rod and/or pistons adapted to distribute oil transported by such a rod. Some use dynamic energy to propel the oil. (The general principle of dynamic energy/pressure pumps is to apply dynamic energy to the medium, such as oil, by scooping it up and propelling it by rapid cyclical motion.) However, none of said patents provide for complete “round trip” oil circulation via this method. They transport oil only one-way. This necessarily limits utility of the oil in cooling the engine, for it must either be slowly metered out so as to prevent a significant amount of it burning with the normal engine combustion, or it must be restricted from the cylinder interior entirely.
Further, dynamical propulsion oil pumps and oil carrying piston rod systems consistently teach their use only in lubricating the piston wrist pins, or lubricating/cooling the bottoms of the pistons. None are designed, as this patent teaches, to provide the primary lubrication to cylinder walls plus a return route for the oil for complete circulation loops. Examples include U.S. Pat. Nos. 2,569,103 and 2,645,213 (to Huber), U.S. Pat. Nos. 4,466,387, 4,502,421, and 4,515,110 (Perry), U.S. Pat. No. 2,865,349 (MacDonald), U.S. Pat. No. 3,633,468 (Burck), U.S. Pat. No. 3,992,980 (Ryan et al), and U.S. Pat. No. 3,930,472 (Athenstaedt), and U.S. Pat. No. 2,899,016 (Swayze).
Additional examples of systems incorporating piston rod oil transport also include pressure sealed walls at the base of their cylinders, as does this patent application. (These sealed walls are also known as “cross heads.”) However, as in those described above, none provide for complete oil circulation cycles to include oil return from the engine cylinder to the sump. Examples of these include U.S. Pat. No. 1,268,056 (Ruether), U.S. Pat. No. 1,827,661 (Kowarick), U.S. Pat. No. 2,064,913 (Hedges), U.S. Pat. No. 2,244,706 (Irving) and U.S. Pat. No. 3,710,767 (Smith).